move immediate hydration to pro

[AbanoubGhadban]

Summary

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Pull Request checklist

Remove this line after checking all the items here. If the item is not applicable to the PR, both check it out and wrap it by ~.

• Add/update test to cover these changes
• Update documentation
• Update CHANGELOG file

Add the CHANGELOG entry at the top of the file.

Other Information

Remove this paragraph and mention any other important and relevant information such as benchmarks.

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[claude]

Code Review: Move immediate_hydration to Pro

Summary

This PR successfully migrates the immediate_hydration configuration option from the open-source React on Rails gem to React on Rails Pro, properly implementing it as a licensed feature.

---

✅ Strengths

1. Clean Architecture

• The new ProUtils.immediate_hydration_config method provides a centralized, safe accessor that returns false when Pro is not available
• Excellent encapsulation - all Pro feature checks go through a single helper method
• The pattern is reusable for future Pro-only features

2. Comprehensive Migration

• Removed immediate_hydration from 5 locations in open-source configuration: Configuration.configuration_hash, attr_accessor, initialize, defaults, and the dummy app
• Added it properly to Pro configuration with DEFAULT_IMMEDIATE_HYDRATION = false
• Updated all 3 call sites (controller.rb, helper.rb, render_options.rb) to use the new helper

3. Test Quality Improvements

• Excellent refactor in test files: replaced around hooks that modified global config with cleaner allow().to receive() stubs
• Tests are now isolated and don't pollute global configuration state
• This is a best practice improvement beyond the core requirements

4. Documentation Updates

• The doctor.rb diagnostic tool now properly separates Pro config from open-source config
• Shows immediate_hydration status in Pro initializer check
• Removed Pro feature from performance config section (appropriate separation)

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🔍 Potential Issues

1. Logic Error in pro_utils.rb (line 28-30) ⚠️

option_enabled = if raw_options[option].nil?
                   # Use the Pro config helper to get the global config value
                   immediate_hydration_config

Problem: This hardcodes immediate_hydration_config for ALL options in PRO_ONLY_OPTIONS, but the method should be dynamic.

Current behavior: Works only because PRO_ONLY_OPTIONS = %i[immediate_hydration] has one element
Future bug: If you add streaming_ssr: true to PRO_ONLY_OPTIONS, it will incorrectly use immediate_hydration_config

Fix:

option_enabled = if raw_options[option].nil?
                   # Dynamically call the Pro config method for this specific option
                   method_name = "\#{option}_config"
                   respond_to?(method_name, true) ? send(method_name) : false
                 else
                   raw_options[option]
                 end

Or simpler for now:

option_enabled = if raw_options[option].nil?
                   send("\#{option}_config")
                 else
                   raw_options[option]
                 end

2. Missing CHANGELOG Entry 📋
Per CLAUDE.md:

Update CHANGELOG.md for user-visible changes only (features, bug fixes, breaking changes, deprecations, performance improvements)

This is a breaking change for users who:

• Use immediate_hydration without Pro license (it will silently stop working)
• Have config.immediate_hydration = true in their open-source initializer (it will raise an error)

Suggested entry:

#### [PR 1996](https://github.com/shakacode/react_on_rails/pull/1996) by [AbanoubGhadban](https://github.com/AbanoubGhadban)

**Breaking Change:** The `immediate_hydration` configuration option is now a React on Rails Pro exclusive feature. If you were using this option without a Pro license, you'll need to either:
1. Remove `config.immediate_hydration = true` from your `config/initializers/react_on_rails.rb`
2. Upgrade to React on Rails Pro and move the setting to `config/initializers/react_on_rails_pro.rb`

The option will be silently ignored if Pro is not installed.

3. PR Description is Template Text 📝
The PR body is still the default template. Please update with:

• What this PR does (moves immediate_hydration to Pro)
• Why (it's a licensed feature)
• Any migration steps for users

---

🎯 Security & Performance

Security: ✅ No concerns. The feature gracefully degrades when Pro is not licensed.

Performance: ✅ Negligible impact. The immediate_hydration_config method is called during component rendering setup, not in hot paths.

---

📊 Test Coverage

Current coverage: ✅ Good

• Tests properly stub the new helper method
• Integration tests verify behavior with Pro features enabled

Recommendation: Consider adding a test case for:

context "when Pro is not available" do
  it "returns false for immediate_hydration_config" do
    allow(ReactOnRails::ProUtils).to receive(:support_pro_features?).and_return(false)
    expect(ReactOnRails::ProUtils.immediate_hydration_config).to eq(false)
  end
end

---

📋 Pre-Merge Checklist

Per CLAUDE.md, before merging:

• Run bundle exec rubocop and fix all violations
• Ensure all files end with newlines
• Update PR description (remove template text)
• Add CHANGELOG entry for breaking change
• Fix the logic bug in pro_utils.rb:28-30
• Consider using /update-changelog command for guided changelog update

---

🎉 Overall Assessment

Quality: High - clean refactoring with good test practices
Risk: Medium - breaking change requires clear communication to users
Recommendation: Approve after addressing the logic bug and adding CHANGELOG entry

The architecture is solid and sets a good pattern for future Pro features. The test improvements (using stubs instead of global config mutation) are a welcome bonus. Great work! 🚀

[justin808]

See #1997.